In related arts, an optical measurement method using flow cytometry (flow cytometer) is utilized to analyze biologically-relevant fine particles such as cells, microbes, liposomes, and the like. The flow cytometer is a device to irradiate fine particles flowing inside a flow passage formed in a flow cell, a microchip, and the like with light, and detect and analyze fluorescence and scattered light emitted from individual fine particles.
The flow cytometer in a related art is adapted to suck sample liquid stored in, for example, a container or a tube by using a sample injection mechanism, a pipetter, or the like and inject the sample liquid into a flow passage of the flow cell or the microchip (refer to Patent Documents 1 and 2). Furthermore, recently the particle analyzer such as the flow cytometer is totally automated, and for example, a device that can automatically perform sampling from a plurality of tubes or wells storing different samples respectively is developed.